hold on.. YOUR DANYA? you hacked into the games code to find the level. (just realized)
Yeah... Not that I hacked into the game's code, most of the stuff in Grouch's video was a little exxagerated. More specifically, I just replaced (for example) the files for the level 1 with different level files, to load each level one by one. When I tried that on the 10th level, I got into this secret level. No "hacking into the game's code" to find that, it wasn't even that complicated.